FIGURE 4.
Involvement of reactive oxygen species (ROS) and nitric oxide (NO) in chitin signalling inArabidopsisguard cells. (a) Effects of 100 units/ml catalase and 100 µM cPTIO on 50 µg/ml chitin‐induced stomatal closure. After treatment, stomatal apertures were observed in epidermal fragments from abaxial surfaces of the treated leaves. Values represent means ± SEfrom three independent experiments;n = 50 apertures per experiment. (b) Effects of catalase and cPTIO on chitin‐induced ROS production in guard cells. Fluorescence images and pixel intensities in guard cells preloaded with 50 µM H2DCF‐DA for 20 min in darkness were recorded. (c) Effects of catalase and cPTIO on chitin‐induced NO production in guard cells. Fluorescence images and pixel intensities in guard cells preloaded with 20 µM DAF‐2DA for 20 min in darkness were recorded. Data of fluorescence pixel intensities are displayed as means ± SE,n = 50 apertures per experiment. Means with different letters denote statistically significant differences among different treatments as determined by analysis of variance (LSD test,p < .05)